Sensor arrays for molecular detection are often desired to contain large numbers of individual sensors. In principle every sensor can be used to detect a different target analyte, but chemical and biological cross reactivity and different dynamic ranges reduce the marginal benefit of each additional sensor of the array.
There is a broad range of biosensors, which are analytical devices and can detect biological analytes with a broad range of detection mechanisms. Biosensors are key elements in diagnostic devices or platforms as they convert a biological signal (e.g., concentration of a target analyte) into an externally measurable signal.
Microfluidic devices are able to perform analytical operations, with a high throughput—essentially through parallelization—and low reagent use. Microfluidic chips use all kinds of materials that contain fluids in a micrometer scale, most commonly polymers (e.g. PDMS, PMMA, Polyolefins), glass and silicon. Most microfluidic analytical devices used for biological analyses employ optical detection rather than solid-state based biosensors.
While there is a broad range of biosensor chips and microfluidic devices available for analytic purposes, very few devices combine both biosensors with microfluidics. Such combined systems have the advantage of directly analyzing biological samples, e.g., by performing microfluidic bioassays.
The biosensors with irremovably fabricated microfluidic features/microfluidic devices on the sensor solid support or similarly a sensor embedded in a microfluidic device are typically fabricated in a process having several formation steps resulting in a device that at least structures microfluidic features on the sensor surface and typically encloses the biosensor in the microfluidic system.
Due to the rapid expansion of solid-state fabrication technologies for substantially planar devices, multiple sensors on a single sensor solid support (e.g. sensor arrays) become more economical to manufacture. With this many sensors on a solid support, a single compartment approach, the marginal benefit of each additional sensor becomes smaller as the higher the number of sensors get. Added constraints such as cross reactivity between analytes and requirements for adapted dynamic ranges for different analytes become more complex to handle with each additional analyte. Therefore, the ability to gain useful information from an additional sensor by detecting an additional analyte decreases. This leads to an effective limit on the number of samples and analytes that can be measured with a single device. In other words, not all of the sensors can be put to their best possible use.
Current microfluidic technology covers the sensor solid support in only one compartment and has not kept up with addressing these sensors more individually. Therefore, there is a need in the art to compartmentalize specific sensors, separated from other sensors, on a substantially planar sensor solid support to get the best use out of each sensor in a sensor support.
Using sensors in specific biological target molecule detection requires to specifically functionalize the individual sensors in sensor arrays to detect the specific target molecules. This required individual functionalization of each sensor in sensor arrays is not practical when multiple sensors in a single closed compartment need to be functionalized with different processes/reagents. Therefore there is a need in the art to functionalize specific sensors individually before compartmentalization into more than one compartments.